I'd like the vector shape tools to simply use the Foreground colour for the stroke and the Background colour for the fill. This would allow very fast creation of shapes with different stroke and fill colours.

Vector shapes in Photoshop and Photoshop Elements are actually vector masks for a color fill layer. This is in part due to the Photoshop family of products being fully raster with some vector support. The vector support in all cases is the vector information acts as a mask, defining an area to fill with pixels.

For the functionality you request a true vector application, like Illustrator or Flash, should be used.